Device for electro-optically monitoring filiform material

ABSTRACT

Device for electro-optically monitoring filiform material alternately stationary and traveling in the longitudinal direction thereof includes a light-sensitive element disposed back of the filiform material, means located in front of the filiform material for subjecting the filiform material to light beams extending in at least two directions thereto, and means for spacing the filiform material, in the traveling condition thereof, closer to the light-sensitive element than when the filiform material is in stationary condition thereof.

United States Patent lnventor Hans Raasch Rheydt, Germany Appl. No.791,738 Filed Jan. 16, 1969 Patented Jan. 19, 1971 Assignee WalterReiners Monchengladbach, Germany Priority Jan. 20, 1968 Germany1,710,131

DEVICE FOR ELECTRO-OPTICALLY MONITORING FILIFORM MATERIAL 6 Claims, 3Drawing Figs.

US. Cl 250/219, 356/200 Int.Cl ..G01b11/10 Field of Search 250/2195,

(inquired), 219L, 219TH; 356/199, 200, 237, 238; 66/163 [56] ReferencesCited UNITED STATES PATENTS 2,413,486 12/1946 Denyssen 250/219X2,438,365 3/1948 Hepp etal. 66/163 3,016,207 1/1962 Comstock 250/219X3,461,299 8/1969 Felix 250/219 3,053,986 9/1962 Loepfe et al 250/239XPrimary Examiner-Walter Stolwein Att0rneys-Curt M. Avery, Arthur E.Wilfond, Herbert L.

Lerner and Daniel J. Tick ABSTRACT: Device for electro-opticallymonitoring filiform material alternately stationary and traveling in thelongitudinal direction thereof includes a light-sensitive elementdisposed back of the filiform material, means located in front of thefiliform material for subjecting the filiform material to light beamsextending in at least two directions thereto, and means for spacing thefiliform material, in the traveling condition thereof, closer to thelight-sensitive element than when the filiform material is in stationarycondition thereof.

DEVICE FOR ELECTRO-OPTICALLY MONITORING FILIFORM MATERIAL My inventionrelates to device for electro-optically monitoring filiform material andmore'particularly such devices wherein the material is subjected from atleast two directions to light influencing a light-sensitive element.

Devices of this general type are employed, for example, for ascertainingthe presence of abnormalities in the filiform material, such as thick orthin spots therein or for inspecting the regular knotting or tying oftwo ends of the filiform material. These devices are generallyassociated with a severing device which severs the filiform. material ifa dimension thereof, such as the diameter, cross section, volume or thelike deviates from a given nominal value.

If the filiform material is a textile yarn, it is known, of course, thatit cannot have any exact uniform cross section but rather is subject tocertain variations in cross section. A specific valueof these variationsis looked upon as being permissible or tolerable. Thus, the device formonitoring textile yarn is so adjusted that deviations within apredetermined tolerance value do not produce any actuating pulse thatwould otherwise result insevering the yarn. Moreover, the length of theyarn portion of abnormal dimension. such as a thickened portion or thelike, is of significance. Thus, for example greatly thickened yarnportions that are very short in length may nevertheless be tolerable,whereas slightly thickened yarn portions of relatively great length canhave a disturbing effect. In order to take such a situation intoaccount, delay circuits for example have been provided which permit theyarn severing device to be activated only after the predeterminedmaximum value of a shading for a specific time period is exceeded. Sincethe speed of the yarn traveling through themonitoring device is known,the tolerable length of a yarn portionof given deviating thickness isascertained in this manner.

A trouble-free operating device of this type for the traveling yarn,however, produces fault shadows when the yarn is at rest i.e. is 'nottraveling in the longitudinal direction thereof through the monitoringdevice.

It has therefore been proposed that the monitoring of the filiformmaterial be interrupted during the time interval in which the filiformmaterial is at rest. This proposal demands considerable expense,however, requiring the monitoring device to be activated immediatelyupon start-up of the machine without permitting an inadmissible orintolerable length of the filiform material to travel therethroughuntested.

It is accordingly an object of my invention to provide device forelectro-optically monitoring filiform material which avoids theforegoing disadvantages of the heretofore known devices of this generaltype and which, more specifically, avoids the undesired insert cuts orunintentional severances of the filiform material at relatively lowcost.

With the foregoing and other objects in view l provide in accordancewith my invention device for electro-optically monitoring filiformmaterial comprising a light-sensitive element, and means for spacing thefiliform material closerto the lightsensitive element, when the filiformmaterial is traveling in the longitudinal direction thereof, than whenthe filiform material is at a standstill. It should be understood thatby the term standstill it is meant not only the absolute rest of thefiliform material but also the faulty movement of the filiform materialin the longitudinal direction thereof i.e. the interrupted or brokentravel of the filiform material. A movement of the filiform material,such as a yarn, transversely to the longitudinaltravel directionthereof, for example when inserting the filiform material into themonitoring device, does not result in any travel of the filiformmaterial in thelongitudinal direction thereof, and is consequentlyrelegated to the category of the standstill of the filiform material.

In accordance with further features of my invention, the spacing meansdefines the spacing of the filiform material from the light-sensitiveelement so that the light beams coming from different directions andimpinging on the filiform material cast orderly shadows thereof on'thelight-sensitive element. When the filiform material is at standstill aswhen the filiform material is being inserted in the monitoring device,the spacing of the filiform material from the light-sensitive element isincreased, however, so that the shadow effects produced on thelight-sensitive element by the individual light beams that extend indifferent directions produce no switching pulse due to theirinsignificance.

, To permit trouble-free measurement, l provide in accordance with afurther feature of my invention a translucent cover for thelight-sensitive element which is spaced at given distance therefrom, thefiliform material being disposed in abutment with the translucent coverwhen the filiform material is traveling in its longitudinal direction soas to define thereby the spacing of the filiform material from thelight-sensitive element.

In accordance with yet another feature of my invention, the translucentcover is provided with inclined end faces so that the path of thefiliform material at the ends of the cover is angled off, and thusattaining not only a reliable abutment for the filiform material at thetranslucent cover but also simultaneously assuring that when severalfiliform materials are being monitored together, they will be disposedparallel to one another in front of the light -scnsitive element andwill in this way be uniformly strongly illuminated.

In accordance with additional features of my invention, in addition tothe cover of the light-sensitive element serving as an abutment memberfor the traveling filiform material, l provide an abutment means for thestationary filiform material which is preferably disposed parallel tothe abutment surface of the translucent cover. When a prism or adiffused lightproducing disc are employed for providing light beamsextending along different paths, the prism or disc can then serve as theabutment means for the stationary filiform material. To insure that thefiliform material will actually abut this abutment means, I furtherprovide in accordance with my invention at least one air nozzle actingon the stationary filiform material. I also provide, in accordance withmy invention, at least one contour member at the translucent cover,against which the traveling filiform material abuts for providing alateral limit to the motion of the filiform material whereby all or atleast the predominant portion of the light beams impinging on thefiliform material from different directions have an exciting effect onthe light sensitive element.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedin device for electro-optically monitoring filiform material, it isnevertheless not intended to be limited to the details shown, sincevarious modifications and structural changes may be made therein withoutdeparting from the spirit of the invention and within the scope andrange of equivalents of the claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawing, in which:

FIGS. l and 2 are respective plan and side elevational views of theelectro-optical device for monitoring filiform material according to myinvention; and I FIG. 3 is an enlarged fragmentary view of FIG. 1.

Referring now to the drawing and first, particularly, to FIGS. 1 and 2thereof, there is shown a light bulb I from which light is passedthrough a lens 2 and a prism 3 to a photoelectric cell 4 protected by atranslucent cover 5. The filiform material that is being monitored isinserted between the translucent cover 5 and the prism 3. Theaforementioned components are so assembled that when the filiformmaterial travels in the iongitudinal direction thereof it follows a pathcorresponding to the dot-dash line E whereas when the filiform materialis at rest such as for example after the filiform material has beeninserted in the measuring device, the filiform material adopts a coursecorresponding to the dot-dash line F It can be observed from theenlarged fragmentary view of FIG. 3 that light beams extend from theprism 3 in two different directions so that the inserted filiformmaterial such as yarn, casts a shadow in both of these directions. Thus,as clearly seen in FIG. 3, only the shadows F, and F," of the yarn F,located closer to the photoelectric cell 4 excites or impinges on thecell. while the shadows F and F produced by the yarn F laterally pass bythe cell 4. In order to define the position F or F of the yarn moreclearly, the yarn when traveling along the path represented by thedot-dash line F lies right at the translucent cover 5, whereas it liesin abutting engagement with the prism 3 when the yarn is at standstill.As can be seen from H0. 2, the path of the yarn corresponding to thedot-dash line F is angled off at the inclined end faces 50 and 5b of thetranslucent cover 5 so that, for example, when two yarns are inserted,assurance is afforded that both of these yarns will travel parallel toone another over the translucent cover 5 and will therefore have uniformspacing from the photoelectric cell 4.

Two air nozzles 6 and 7 are also provided as shown in FIG. 2. in theform of suction nozzles which act on the stationary yarn F and assurethe abutment of this yarn F against the prism 3. There can furthermorebe seen in FIG. 3, two lateral contour members 8 and 9 which extendbetween the prism 3 and the translucent cover 5 so as to limit thelateral movement of the yarn F to a range within which both shadows F.and F," will safely fall on the photoelectric cell 4. The laterallimiting contour member 8 is formed with an insert opening 8a throughwhich the yarn can be inserted in the measuring device.

The hereindescribed and illustrated device for monitoring the orderlyknotting of yarn in an automatic yarn-winding machine, for example,operates in the following manner: The yarn coming from the take up coilor from the supply coil is inserted through the insert slot 8a into themeasuring device by means of a gripper arm simultaneously inserting theyarn into the knotting device, and thereby assumes the positionrepresented by the dot-dash line F in which the shadow image on thephotoelement of the cell 4 is at least so small that even uponaccidental insertion of a deviating thick portion of the yarn, noactivating pulse for the non nonillustrated yarn-severing device will beproduced. The suction nozzles 6 and 7 thereby hold the yarn tightlyagainst the prism 3, at startup of the winding station of the automaticwinding machine, the yarn tension increases so that the yarn, by beingdrawn taut between the nonillustrated yarn guiding members of thestation. adopts the course represented by the dot-dash line F Thus thefull shadow formation or shading action upon the photoelement of thecell 4 is immediately attained.

As aforementioned, my invention is not limited to the illustrated andaforedescribed embodiment only. In the figures, the light emanating fromthe lamp 1 impinges on the filiform material from two directions bymeans of the prism 3. However, a prism can also be employed whichdirects light beams from more than two directions onto the yarn.Furthermore, my invention is also suited to the use of several lightsources for producing the plurality of light beams. It is in fact alsopossible to employ diffused light which will impinge on the yarn from avirtually infinite number of directions. Also in such a case, it wouldbe found, in accordance with the invention. that the shadow effect ofthe yarn in the position F is considerably less than in the the positionF,, and accordingly no switching or activating pulse is released by thephotoelectric cell 4 when the yarn is in the position F I claim:

l. Device for electro optically monitoring continuous filiform materialalternately stationary and traveling in the longitudinal directionthereof. comprising a light-sensitive element disposed back of thecontinuous filiform material. means located in front of the continuousfiliform material for subjecting the continuous fi iform material tolight beams extending in at least two directions thereto. and means forspacing the continuousfiliform material in the travelin conditionthereof closer to said light-sensitive element than w en the continuousfiliform material is in the stationary condition thereof.

2. Device according to claim I, comprising a translucent cover for saidlight-sensitive element spaced a predetermined distance therefrom, thefiliform material in said traveling condition thereof being in abuttingrelation to said translucent cover so as to determine the spacing fromsaid light-sensitive element of the filiform material in said travelingcondition thereof.

3. Device according to claim 2 wherein said translucent cover hasinclined end faces, and the filiform material in said travelingcondition thereof follows a path that is angled away at said inclinedend faces.

4; Device according to claim 2 including abutment means spaced from saidsaid light-sensitive element and being adopted for engagement inabutting relationship therewith by the filiform material in saidstationary condition thereof.

5. Device according to claim 4 including air nozzle means coordinatedwith said abutment means for acting on the filiform material in saidstationary condition thereof.

6. Device according to claim l including at least one contour membercoordinated with said means for spacing from said light-sensitiveelement the filiform material in the traveling condition thereofforlimiting a lateral movement of the filiform material.

1. Device for electro-optically monitoring continuous filiform material alternately stationary and traveling in the longitudinal direction thereof, comprising a light-sensitive element disposed back of the continuous filiform material, means located in front of the continuous filiform material for subjecting the continuous filiform material to light beams extending in at least two directions thereto, and means for spacing the continuous filiform material in the traveling condition thereof closer to said light-sensitive element than when the continuous filiform material is in the stationary condition thereof.
 2. Device according to claim l, comprising a translucent cover for said light-sensitive element spaced a predetermined distance therefrom, the filiform material in said traveling condition thereof being in abutting relation to said translucent cover so as to determine the spacing from said light-sensitive element of the filiform material in said traveling condition thereof.
 3. Device according to claim 2 wherein said translucent cover has inclined end faces, and the filiform material in said traveling condition thereof follows a path that is angled away at said inclined end faces.
 4. Device according to claim 2 including abutment means spaced from said said light-sensitive element and being adopted for engagement in abutting relationship therewith by the filiform material in said stationary condition thereof.
 5. Device according to claim 4 including air nozzle means coordinated with said abutment means for acting on the filiform material in said stationary condition thereof.
 6. Device according to claim l including at least one contour member coordinated with said means for spacing from said light-sensitive element the filiform material in the traveling condition thereof for limiting a lateral movement of the filiform material. 